Locking has a few other disadvantages. When a thread is waiting for a lock, it cannot do anything else. If a thread holding a lock is delayed (due to a page fault, scheduling delay, or the like), then no thread that needs that lock can make progress.
Par ailleurs, What are the dangers of an unlocked workstation?
Someone with the wrong intentions can cause a lot of damage in 20 minutes with access to an unlocked work computer. An experienced hacker could install malicious software in a matter of seconds.
Ainsi, What are the 2 disadvantages or problems of lock based protocols? Problems associated with Simple locking: Data inconsistency between multiple transactions. Deadlock, a situation where the transactions try to access lock on already locked data items. No guarantee of serializability (i.e. execution of a concurrent transaction equivalent to that of a transaction executed serially)
What is disadvantages of locking Mcq? Answer: Locking has a poor degree of concurrency. It in fact has no concurrency at all.
De plus, Why you should never leave your computer unlocked? Not locking your computer is like surrendering access of your files, whether personal, confidential or public to unauthorized persons. Next time you leave your computer unlocked just remember, anyone can gain access to your computer and modify, remove or even share data from your computer.
How long it is OK to leave your PC unlocked and unattended?
It will be ok for 1 to 2 hour. If you left it more, the memory cache can be increased.
Which lock locks the item from change but not from read?
Discussion Forum
Que. | Which of the following locks the item from change but not from read? |
---|---|
b. | Explicit lock |
c. | Exclusive lock |
d. | Shared lock |
Answer:Shared lock |
What are the limitations of two-phase locking protocol?
Two-phase locking may also limit the amount of concurrency that occurs in a schedule because a Transaction may not be able to release an item after it has used it. This may be because of the protocols and other restrictions we may put on the schedule to ensure serializability, deadlock freedom, and other factors.
What is two-phase locking and how does it guarantee serializability?
In databases and transaction processing, two-phase locking (2PL) is a concurrency control method that guarantees serializability. It is also the name of the resulting set of database transaction schedules (histories).
What is the advantage of locking?
Locking is a mechanism to ensure data integrity while allowing maximum concurrent access to data. It is used to implement concurrency control when multiple users access table to manipulate its data at the same time.
How do we generally recover from deadlock?
Recovery from Deadlock in Operating System
- Process Termination: To eliminate the deadlock, we can simply kill one or more processes. For this, we use two methods:
- Resource Preemption: To eliminate deadlocks using resource preemption, we preempt some resources from processes and give those resources to other processes.
Why lock your computer when you walk away?
Why Should You Lock Your Desktop? If you walk away from your computer and do not lock it or log off, it poses a security risk to you and the college. Someone can use your computer in an unauthorized way even if you are away for a few minutes, such as: Send email from your account.
What technology can prevent a hacker from using your computer when you don’t have it with you?
Firewalls. A firewall is a software program or piece of hardware that blocks hackers from entering and using your computer. Hackers search the internet the way some telemarketers automatically dial random phone numbers.
What will happen if I lock my computer?
Locking your computer keeps your files safe while you are away from your computer. A locked computer hides and protects programs and documents, and will allow only the person who locked the computer to unlock it again. You unlock your computer by logging in again (with your NetID and password).
How do you keep windows unlocked?
- Click « Start | Control Panel | System and Security | Power Options. »
- Click “Require a password on wakeup” in the task pane of the « Select a power plan » page.
- Click the bubble next to “Don’t require a password” on the « Define power buttons and turn on password protection » page.
How long should you leave a PC on?
“It depends on how often you use it,” explains Geek Squad agent Steven Leslie. “If you use your computer multiple times per day, it’s best to leave it on. If you use it for a short time — say an hour or two — just once a day, or even less, then turn it off.”
What does process mean in computing?
A process is an instance of a program running in a computer. It is close in meaning to task , a term used in some operating systems. In UNIX and some other operating systems, a process is started when a program is initiated (either by a user entering a shell command or by another program).
Which of the phase is transaction in if it may obtain locks but may not release any?
Explanation: If a transaction may obtain locks but may not release any locks then it is in growing phase. Growing phase is a phase in two phased locking protocol.
When two transactions are being processed against the database at the same time?
When two transactions are being processed against the database at the same time they are termed concurrent transactions.
Which language most DBMS use to help its users access data?
Query language refers to any computer programming language that requests and retrieves data from database and information systems by sending queries.
What are the benefits and disadvantages of strict two-phase locking?
16.3 What benefit does strict two-phase locking provide? What disadvantages re- sult? Answer: Because it produces only cascadeless schedules, recovery is very easy. But the set of schedules obtainable is a subset of those obtainable from plain two phase locking, thus concurrency is reduced.
Which of the following rules apply to the two-phase locking protocol?
What rule applies to the two-phase locking protocol? Two transactions cannot have conflicting lock. No unlock operation can precede a lock operation in a different transaction. No data is affected until all locks are released.
What is 2 phase locking protocol?
2PL locking protocol
Every transaction will lock and unlock the data item in two different phases. Growing Phase − All the locks are issued in this phase. No locks are released, after all changes to data-items are committed and then the second phase (shrinking phase) starts.